Mediterranean diet may counteract genetic risk of stroke

The Mediterranean diet has often been touted for its heart healthy benefits, and now, new research has revealed that the cuisine may also counteract a person’s genetic risk for stroke.

Modeled after the traditional cooking style of countries surrounding the Mediterranean Sea, the diet consists of previously established healthy food items – such as fruits, vegetables and fish – but with an added splash of extra virgin olive oil and nuts (primarily walnuts).

“The Mediterranean diet is one of the main alternatives we have in terms of healthy diets,” study author Jose Ordovas, director of the Nutrition and Genomics Laboratory at the USDA Human Nutrition Research Center on Aging at Tufts University, told FoxNews.com. “In the United States, especially, the diet being pushed is the low-fat diet. But you look in the literature, and it’s not a perfect diet.”

In order to provide more definitive proof of the Mediterranean diet’s advantages, Ordovas and his colleagues at Tufts, along with researchers from the CIBER Fisiopatologia de la Obesidad y Nutricion in Spain, investigated whether genetics contributed to the cardiovascular benefits of the diet.

In a large controlled, randomized study, more than 7,000 men and women from Spain were assigned to either a Mediterranean diet or a low-fat diet for five years. During the study period, the participants were given frequent food questionnaires, and they were monitored for cardiovascular illnesses, strokes and heart attacks.

The study cohort also underwent genetic testing prior to the beginning of the study to determine whether or not they possessed a variant in the Transcription Factor 7-Like 2 (TCF7L2) gene. Implicated in metabolic conditions like diabetes, TCF7L2 has also been loosely linked with cardiovascular disease. Of the study’s participants, 14 percent were homozygous carriers, meaning they had two copies of the gene variant.

“The mutation can be in one copy or two copies or no copies,” Ordovas explained. “The major effect is found in those people who have mutated both copies. No mutation is fine, but if you have one copy mutated, you have an increased risk. If you have two copies mutated, that is when you’re in trouble.”

Because the gene is so strongly associated with diabetes and cardiovascular illness, the research team believed that it could potentially be influenced by dietary changes.

After analyzing results of the five-year study, the researchers discovered that people with two copies of the TCF7L2 variant experienced a greatly reduced number or strokes when they adhered to the Mediterranean diet. However, if these individuals adhered to the low-fat diet, their risk of stroke was three times greater than individuals with one or no copies of the genetic variant.

Ordovas theorized that the addition of extra virgin olive oil and nuts to the other traditionally healthy food items included in the Mediterranean diet is what caused the gene variant not to be expressed.

“In the case of the olive oil, while we have dietary fat that is very mild, the virgin olive oil contains many other elements and antioxidants that may act over the expression of the gene – creating the beneficial effects,” Ordovas said. “It’s the same with the nuts. They are rich in fat but also rich in minor components that may influence expression of the gene. They act over inflammation, over lipid levels and so on.”

While Ordovas does not suggest that everyone must adhere to the Mediterranean diet, he does advise people with a history of cardiovascular illness to try to incorporate some of the cuisine’s food items into their daily routine.

“It may not be necessary to change their entire diet, but they should at least include in their diets elements of the Mediterranean diet we had mentioned – primarily the olive oil and nuts. Just remove some of the more negative aspects you have in your diet to include some of these components, and you can compensate for your risk.”